PITA Fiscal Year 2008 Projects - Product and Process Design and Optimization

High Performance Polyurethane Elastomers based Biologically Inspired Repeatable Fiber Adhesives

Principal Investigators: Metin Sitti, Maarten P. De Boer

Fibrillar adhesives on the feet of geckos and other animals have been of great interest because they can repeatedly attach to wide range of surfaces with controllable adhesion strength in various environments including vacuum and leave no residue. Furthermore, fibrillar adhesives are self-cleaning, which allows for long lifetime and repeated use without significant performance degradation. Although there have been many recent works on analyzing and fabricating synthetic fibrillar adhesives in literature, the adhesion performance of current synthetic fibrillar adhesive prototypes is significantly inferior than the biological foot-hairs on repeatability and adhering to micro/nanoscale rough surfaces. Therefore, this proposal aims to fabricate and demonstrate high performance polyurethane elastomer fibrillar adhesives similar to their biological counterparts. Three research objectives are proposed in this project: 1) Developing a design methodology for repeatable fibrillar adhesives; 2) Fabrication of single- and two-layer polymer elastomer fiber arrays using optical and interference light lithography methods; 3) Macroscale adhesion characterization of the fabricated polymer fiber arrays using a custom adhesion measurement device.

This project would have many potential near term commercial repeatable adhesive applications in biomedical, space, textile, product design, sports, climbing, robotics, entertainment, and home development areas. Since this adhesive is strong, dry, repeatable, leave no residue, and self-cleaning, it would be a unique adhesive product. As commercialization of this biologically inspired nanomaterial, Bayer Materials Science LLC would be the industrial participant in this project. Bayer would provide support for improving the performance of the fabricated elastomer adhesives by tailoring the elastomer material properties for specific applications. A CMU based start-up company will be formed to manufacture and commercialize this new adhesive material in Pennsylvania.